Steel 42CrMo Annealed
Temper
GB 42CrMo
Softest condition — choose for heavy machining, deep drilling or cold upsetting before final hardening.
Values for the Annealed condition
Other 42CrMo tempers and conditions
42CrMo is listed in 9 conditions; see the grade overview at 42CrMo.
Compare all 9 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
AnnealedThis page full/spheroidize anneal, ≤217 HB | Softest condition — choose for heavy machining, deep drilling or cold upsetting before final hardening. | 450 | 700 | 22 | 200 HB | — |
HRDefault Hot rolled | Cheapest stock form for parts that will be heat treated (or lightly loaded) after machining. | 570 | 880 | 15 | 22 HRC | — |
austenitize ~860 °C, air cool | Uniform fine-grain structure for forgings and large sections before final Q&T or for moderate-strength service. | 650 | 1,000 | 18 | 29 HRC | — |
Cold rolled | Thin strip/plate form (often annealed after rolling) for stamped or laser-cut blanks that will be hardened later. | 660 | 820 | 12 | 23 HRC | 7.8 % IACS |
Cold drawn | Close tolerance, bright surface bar for shafting and turned parts that need little further machining. | 780 | 930 | 11 | 26 HRC | — |
Tempered high for toughness / sour service | Pick when NACE MR0175 (≤22 HRC alternative not required) or maximum impact toughness and machinability after heat treatment matter. | 860 | 1,000 | 17 | 30 HRC | — |
Quenched and tempered | Standard high-strength delivery condition for shafts, gears and bolting where 1080 MPa min tensile is specified. | 960 | 1,120 | 14 | 36 HRC | — |
Q&T + gas/plasma nitrided | Choose for wear surfaces (gears, spindles, hydraulic rods) where the Q&T core strength is kept and a hard, distortion-free case is added; hardness values below are surface, core equals Q&T. | 960 | 1,120 | 13 | 36 HRC | — |
Tempered for higher strength | Highest practical hardness that keeps useful toughness — gears, couplings, high-strength studs and drill collars. | 1,050 | 1,180 | 12 | 36 HRC | — |
What is 42CrMo Annealed?
42CrMo Annealed is 42CrMo in the Annealed temper — softest condition — choose for heavy machining, deep drilling or cold upsetting before final hardening. 42CrMo Annealed has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 52% of steel grades. Elongation at break is 22% and the elastic modulus is 210 GPa (30.5 Msi). 42CrMo Annealed has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,416°C (2,581 °F). HR is the default condition FabDigit quotes; Annealed is available on request or by drawing note.
Limitations
- Low fracture toughness — 60 MPa·√m (54.6 ksi·√in), worse than 78% of steel grades
42CrMo Annealed properties
Typical room-temperature values for 42CrMo Annealed; 13 are specific to this condition. Other listed values are 42CrMo reference data and may not represent this condition. Bars are the position among steel grades.
Physical3
42CrMo Annealed has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,416°C (2,581 °F).
Mechanical15
42CrMo Annealed has a yield strength of 450 MPa (65.3 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 52% of steel grades. Elongation at break is 22% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
42CrMo Annealed is rated for continuous service to 425°C (797 °F). It conducts heat at 42.6 W/m·K (24.6 BTU/hr·ft·°F), worse than 51% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
42CrMo Annealed conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of 42CrMo Annealed takes about 29 MJ of energy and emits 2.3 kg of CO₂ — less than 53% of steel grades. Typical recycled content is 30%.
Manufacturability7
42CrMo Annealed's machinability is good (58/100, better than 75% of steel grades); weldability fair (35/100); formability fair (40/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with 42CrMo Annealed
Is 42CrMo easy to machine?
Machine in the annealed or ≤32 HRC Q&T condition with rigid setups, carbide inserts and generous coolant; above 38 HRC switch to grinding or CBN.
Can 42CrMo be welded?
Weldable with low-hydrogen consumables but requires 200–350 °C preheat, controlled interpass temperature and immediate post-weld temper (~600 °C) to avoid HAZ cracking.
Can 42CrMo be formed, bent or molded?
Hot forge/upset at 1150–850 °C then normalize; cold bending is limited — anneal first and use generous radii.
What surface finishes work on 42CrMo?
No anodizing; use black oxide, manganese phosphate, zinc or hard-chrome plating (bake to avoid hydrogen embrittlement above ~35 HRC), nitriding or paint for corrosion protection.
42CrMo chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| C | 0.38 – 0.45 | 0.42 |
| Si | 0.17 – 0.37 | 0.27 |
| Mn | 0.5 – 0.8 | 0.65 |
| Cr | 0.9 – 1.2 | 1.05 |
| Mo | 0.15 – 0.25 | 0.2 |
| Niresidual limit | ≤ 0.3 | |
| Curesidual limit | ≤ 0.3 | |
| P | ≤ 0.03 | |
| S | ≤ 0.03 | |
| Fe | balance |
42CrMo Annealed — frequently asked
What is 42CrMo Annealed used for?
42CrMo Annealed is typically used for drive shafts, crankshafts, gears and pinions, high-strength bolting and studs, hydraulic cylinder rods and drill collars. In short: workhorse Cr-Mo machining bar.
What is the yield strength of 42CrMo Annealed?
42CrMo Annealed has a typical yield strength of 450 MPa (65.3 ksi) and a tensile strength of 700 MPa (102 ksi) — stronger than 52% of steel grades. Strength varies by condition: see the 9 listed tempers.
Is 42CrMo Annealed easy to machine?
Reasonably — machinability is rated good (58/100, better than 75% of steel grades). Machine in the annealed or ≤32 HRC Q&T condition with rigid setups, carbide inserts and generous coolant; above 38 HRC switch to grinding or CBN.
Can 42CrMo Annealed be welded?
With care — weldability is rated fair (35/100). Weldable with low-hydrogen consumables but requires 200–350 °C preheat, controlled interpass temperature and immediate post-weld temper (~600 °C) to avoid HAZ cracking.
What surface finishes work on 42CrMo Annealed?
No anodizing; use black oxide, manganese phosphate, zinc or hard-chrome plating (bake to avoid hydrogen embrittlement above ~35 HRC), nitriding or paint for corrosion protection.
Can 42CrMo Annealed be formed, bent or molded?
Hot forge/upset at 1150–850 °C then normalize; cold bending is limited — anneal first and use generous radii.
What is the maximum service temperature of 42CrMo Annealed?
42CrMo Annealed is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between 42CrMo-HR and 42CrMo-CD?
HR is the default condition — cheapest stock form for parts that will be heat treated (or lightly loaded) after machining. CD: close tolerance, bright surface bar for shafting and turned parts that need little further machining. Yield strength is 570 MPa in HR versus 780 MPa in CD.
Can FabDigit make parts in 42CrMo Annealed?
Yes — 42CrMo Annealed is available for CNC machining and sheet metal with instant online pricing. Upload a STEP file to get a price and a DFM check.
Sources
- GB/T 3077 Alloy structural steels — SAC (2015)
- EN 10083-3 (42CrMo4, 1.7225) — CEN (2006)
- ASTM A29/A29M & SAE J404 (4140) — ASTM / SAE (2020)
- ASM Handbook Vol.1 Properties and Selection: Irons, Steels — ASM International (1990)
- ASM Handbook Vol.19 Fatigue and Fracture — ASM International (1996)
- Machinery's Handbook, machinability ratings — Industrial Press (2020)
- NACE MR0175/ISO 15156 hardness limits for sour service — NACE/ISO (2015)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.